1. Field of the Invention
The present invention relates to a printer and a printing system, and more particularly to a printer and a printing system suitable for printing a printing job having some secret.
2. Description of the Related Art
These days, a printing system in which a printer is shared by means of a network has been increasingly used. Namely, by connecting a plurality of computers as clients to one network and connecting, for example, one printer to this network, one printer can receive printing jobs from the plurality of clients and perform printing.
In the printing system using this network, there is a certain distance between the clients and the printer in some cases, and hence a function of confidential printing is supported providing against a case where a printing job with some secret which others are not permitted to look at is printed.
In this confidential printing, when a user transmits a printing job from the client to the printer, for example, confidential attribute information indicating confidential printing, user information and a password are added thereto. The printer which has received this printing job does not immediately start printing based on this printing job, but temporarily saves it as printing job data in a hard disk. When the user comes to the printer and inputs right user information and password from an operation panel of the printer, the printer reads the printing job data out of the hard disk and starts printing. This prevents the printing result of the printing job to be seen by others before the user which has transmitted the printing job arrives at the printer.
In printers supporting such a function of confidential printing, there is a printer which can be set to still hold the printing job in the hard disk after printing. Namely, there is a printer which can be set to save the printing job in the hard disk so that even the printing job which has been printed can be printed again at the request of the user. After a lapse of a given period of time or when a given amount of printing jobs are held, the printing jobs are deleted in sequence from the hard disk.
When the aforesaid confidential printing is performed by the printer having such a hold function, even a printing job of secret confidential printing is held as printing job data in the hard disk after printing is completed. In this case, it can not be said that there is no possibility that a third person with dishonest intentions looks surreptitiously at the printing job data, which has been already printed but still held in the hard disk, forcibly by some means.